A conventional automatic interpretation method using a smart phone is disadvantageous in that a user has to use both hands because he or she has to run an automatic interpretation app by touching the interface of the screen of the automatic interpretation app while holding a smart phone with his or her hands. Meanwhile, users frequently have to use both hands in order to carry bags or show passports while traveling. In such situations, the inconvenience that is caused by performing the interpretation using a smart phone while holding the smart phone with both hands is a factor that detracts from the utility of the automatic interpretation method in spite of its very useful automatic interpretation function. Furthermore, automatic interpretation using a smart phone is commonly performed in the form of bidirectional automatic interpretation in which a first person gives his or her smart phone to a second person, the second person speaks using the smart phone and the first person listens to a synthesized voice output from the smart phone. This is a factor that makes the bidirectional automatic interpretation unnatural.
Korean Patent Application Publication No 10-2010-0068965 discloses an automatic interpretation apparatus and method. As described above, there is a need for automatic interpretation technology using a hands-free method for resolving inconvenience in the use of automatic interpretation in a typical smart phone environment.